1. Field of the Invention
The present invention relates to the field of vehicle maintenance, and more specifically, to performing fluid exchanges with vehicular subsystem components having fluid reservoirs such as automatic transmission fluid and power steering fluid systems.
2. Description of Related Art
Automatic transmissions and other vehicular fluid system components frequently require servicing such as replacing used fluid with fresh fluid in order to properly maintain them and extend the life of the component and associated vehicle. Early attempts at developing automatic transmission fluid transfer machines often resulted in relatively lengthy and complicated procedures. Many of these devices relied upon compressed gases to circulate the fluid and thus required some sort of compressed air source adding to the device""s complexity. Such early attempts also required significant manual operation and supervision as the operator had to continually monitor gauges and other instruments to monitor the fluid flow to achieve the desired performance.
While some of these devices proved satisfactory for their time, the next level of automatic transmission fluid transfer machines introduced a degree of automation to the fluid exchange process thus reducing the extent of operator intervention. However, the plumbing proposed in an effort to automate the process and perform the steps typically associated with a complete automatic transmission fluid service, typically employed a relatively large number of plumbing components such as multiple dedicated pumps, gauges, and several valves. While many of these devices have also proven satisfactory in their performance there remains a push for reducing the number of components, costs associated with manufacture and maintenance, and reducing the overall assembly time while maintaining the capability to perform the desired procedures.
Efforts to resolve this long standing problem led to the introduction of a number of devices of the single pump variety. Some examples of these single pump devices can be found in U.S. Pat. Nos. 5,482,062 and 5,337,708 to Chen; U.S. Pat. No. 5,447,184 to Betancourt; U.S. Pat. No. 5,472,064 to Viken; U.S. Pat. No. 6,035,903 to Few, owned by assignee of this application; and Japanese Unexamined Patent Application No. 2-72299. It is clear from a review of the devices shown in these patents that, while success was achieved in reducing some number of components, such as the pumps, it was necessary to increase the remaining plumbing in order to perform the necessary fluid transfer processes such as complete fluid exchange, recirculation, and draining both used and new fluid tanks or such desired processes could not performed using a single pump. Frequently a separate drain pump or a more complicated and costly reversible pump has been incorporated to perform the desired fluid servicing tasks. While some of these devices, such as that described in U.S. Pat. No. 6,035,903, have proven satisfactory in the field, there remains the ever present need to develop a fluid changing apparatus with a minimal number of components to reduce costs, maintenance, and assembly time, yet still perform the fluid servicing procedures associated with an automatic transmission service.
What is needed is a fluid exchanging apparatus configured to conveniently address the needs of the fluid change operator, such as faster pump speeds and reduced maintenance time, particularly through a reduction in the number of overall couplings and associated hose length requirements, using a single pump configuration integrated into a relatively minimal component fluid transfer system.
In accordance with the present invention, an apparatus for performing fluid exchange servicing functions for a vehicle having a fluid reservoir is described herein and more particularly for servicing the transmission and power steering components of a vehicle system. Such fluid servicing apparatus generally includes a manifold defining a number of service ports and a fluid transfer circuit defining a plurality of pathways for transporting fluid therebetween wherein select ports may be coupled to new and used fluid tanks and other select ports may be coupled to an inlet and outlet of the fluid reservoir to be serviced. The manifold body includes a pump cavity for housing a pump body directly coupled to a pump motor. The pump cavity includes first and second pump ports integrated into the fluid transfer circuit. A fluid flow rate control device is interposed in the fluid transfer circuit and is selectively operable to place each of the ports in communication with at least one other of the ports. The pump motor and fluid flow rate control device are selectively operable to circulate fluid through the fluid transfer circuit and routing fluid between the ports to perform a variety of fluid related servicing procedures.
In one particular embodiment, the pump cavity is defined within an extension to the manifold body and the pump body is a vane pump that is engageable with the drive shaft of the pump motor.
One aspect of the present invention is the incorporation of first and second valves acting in tandem to direct fluid through the fluid transfer circuit and between the ports.
In another embodiment of the present invention, a proportional solenoid valve is interposed in the fluid transfer circuit to selectively adjust the rate of fluid flow passing therethrough.
Another embodiment of the present invention includes a manifold with an auxiliary power steering fluid drain pathway and a reversible pump motor for draining used power steering fluid from a power steering reservoir.
Another feature of the present invention is the incorporation of a processor receiving fluid level feedback signals from first and second sensors in communication with the new and used fluid tank. The processor is programmed to automatically perform the fluid exchanging process based on at least one of the feedback signals by selectively operating either the motor or the fluid flow rate control device or a combination of both.
Other features and aspects of the present invention will become apparent with further reference to the following drawings and specification.